[N₂H₅]⁺₂[N₄C−NN−CN₄]^2-:  A New High-Nitrogen High-Energetic Material

Abstract

The reaction of [N(2)H(5)](+)(2)[SO(4)](2-) with barium 5,5'-azotetrazolate gave new high-energy-density materials (HEDM) based on the 5,5'-azotetrazolate dianion. The dihydrazinium salt of [N(4)C-N=N-CN(4)](2-) 1, its dihydrate 2, and its dihydrazinate 3 were prepared in high yield. Synthesis in water afforded yellow needles of [N(2)H(5)](2)(+)[N(4)C-N=N-CN(4)](2-).2H(2)O (2): monoclinic, P2/c, a = 8.958(2) A, b = 3.6596(7) A, c = 16.200(3) A, beta = 96.834(3) degrees, V = 527.3(2) A(3), Z = 2; synthesis in anhydrous hydrazine gave yellow [N(2)H(5)](2)(+)[N(4)C-N=N-CN(4)](2-).2N(2)H(4) (3): triclinic, P1, a = 4.6208(6) A, b = 8.585(1) A, c = 9.271(1) A, alpha = 108.486(2) degrees, beta = 95.290(2) degrees, gamma = 102.991(2) degrees, V = 334.51(8) A(3), Z = 1. The compounds were characterized by elemental analysis and vibrational (IR, Raman) and multinuclear NMR spectroscopy ((1)H, (13)C, (14)N, (15)N). The new compounds represent new high-nitrogen HEDMs with one of the highest nitrogen contents reported to date ([N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-) 85.2%; [N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-).2H(2)O 73.3%; [N(2)H(5)](+)(2)[N(4)C-N=N-CN(4)](2-).2N(2)H(4) 85.7%). The standard heat of formation of the solvate-free compound 1 was computed at the MP2(FULL)/6-311+G(d,p) level of theory to be DeltaH degrees (f) = 264 kcal mol(-1), which translates to 1147 kcal kg(-1) and is one of the highest ever reported. The compounds are stable at room temperature, almost insensitive to friction and impact, but detonate violently when the explosion is initiated, e.g., by rapid heating over the decomposition temperature or by using an initiator.

Structures and Energetic Properties of Two New Salts Comprising the 5,5'-Azotetrazolate Dianion

“…After short reaction times, bright yellow crystals of 2 ( Figure 6) formed in 86% isolated yield. was due to the asymmetric C-N=N stretching vibration of the azotetrazolate dianion [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33]. Bands in the range of 3127 cm are typical for the NH bonds in the 1H-1,2,4-triazole-1-carboxamidine cation.…”

“…Both the 1 H and 13 C NMR spectra were in good agreement with the expected structure. For example, the 1 H NMR spectrum showed a multiplet at δ 7.95 ppm for the phenyl hydrogens in para-position and a broad multiplet at δ 7.83-7.67 ppm can be assigned to the asymmetric N-C=N stretching vibration of the tetrazole ring, while a strong band at 724 cm −1 is characteristic for the asymmetric C-N=N stretching vibration of the azotetrazolate dianion [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33].…”

Initial decomposition reaction of di-tetrazine-tetroxide (DTTO) from quantum molecular dynamics: implications for a promising energetic material

“…[1][2][3][4][5][6][7][8][9] In addition, the last few years has seen similar progress in predicting and explaining the detailed reaction mechanisms, selectivity, and activity of organometallic reactions in solvents that have guided experiment and been conrmed by experiment. [10][11][12][13] There has also been signicant progress in explaining key aspects of heterogeneous catalysts that have helped somewhat with guiding experiment with some conrmation from experiment.…”

Synthesis and Crystal Structures of New 5,5'-Azotetrazolates

“…These salts typically contain cations such as hydrazinium [3][4][5], ammonium and guanidinium [6], triazolium [7][8][9][10], tetrazolium [11,12], or tetraaminopiperazinium [13], sometimes involving additional azido groups [6,10]. Preferred anions are-beside azide, nitrate, perchlorate and picrate-dinitramide [7], nitroazolates [7,10,14,15], dianions such as 5,5'-bis(tetrazolate) [16] and, in OPEN ACCESS particular, 5,5'-azotetrazolate [3][4][5][6]11,12,16]. The synthesis of 5,5'-azotetrazolates was first reported by Thiele [17].…”

“…Numerous crystal structures of 5,5'-azotetrazolate salts [3][4][5][6][7][8][11][12][13]16,20,21] have been reported, including a series of metal salts; specifically, alkali and alkaline earth metals [22,23], lanthanoids [24][25][26], Pb [27], Tl [28], Mn [29], Fe [30], Cu and Cd [31] form crystalline salts.…”